An Adaptive Positive and Negative Dual-Output Charge Pump

An adaptive positive and negative dual-output charge pump circuit is developed based on the traditional positive and negative dual-output charge pump (CP) circuit through load monitoring and dynamic adjustment of the transistors used for the pump capacitors charging. Firstly, the circuit's driving ability is enhanced by alternately charging and discharging capacitor using different transistors. Furthermore, the boosted positive output voltage serves directly as a power supply for generating the negative output. Finally, the utilization of large transistors for charging the pump capacitor under heavy load and small transistors under light load enables the sustained output of the CP, eliminating the adverse effects of intermittent pumping on response speed and output ripple. It also reduces power consumption under light load conditions when using small transistors for charging the pump capacitor, consequently leading to higher conversion efficiency. The proposed adaptive positive and negative dual-output CP circuit is designed based on the SMIC 180 nm process, with a chip area of $\mathbf{1656} \ast \mathbf{637}\ \boldsymbol{\mu} \mathbf{m}\mathbf{2}$. Simulation results show that the circuit achieves an efficiency above 80% within a load current range of 0–120 mA.